JPH05202828A - Auxiliary air supply device for engine - Google Patents

Abstract

PURPOSE:To adjust the volume of auxiliary air fed into an injection in accordance with an operating condition by communicating and opening the inlet port of an auxiliary air passage having an outlet port communicated and opened to an injector, at a specified position in an intake-air passage and with a specified sectional area. CONSTITUTION:Auxiliary air is mixed into fuel fed into an injector 24 so as to atomize fuel. In an auxiliary air supply device 46, an auxiliary air passage 56 has an outlet port communicated and opened to the injector 24 disposed in an intake-air passage 20, downstream of an throttle valve 10 in an engine 2, and an inlet port which has a specified sectional area and which is opened and communicated to the intake-air passage 20 at a specified position so that the volume of auxiliary air may be adjusted in accordance with an operating condition of the engine 2. Thereby it is possible to suitably adjust the volume of auxiliary air fed into fuel injected and fed into the injector 24, in accordance with an operating condition of the engine 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auxiliary air supply device for an engine, and more particularly, it is possible to appropriately adjust the amount of auxiliary air mixed with fuel injected and injected by an injector according to the operating condition of the engine with a simple structure. The present invention relates to an auxiliary air supply device for an engine.

[0002]

2. Description of the Related Art As a device for supplying fuel to an engine, there is a device for injecting and supplying fuel by an injector. There is an engine auxiliary air supply device for injecting and supplying fuel by such an injector, in which auxiliary air is mixed with fuel injected and supplied by the injector to atomize the fuel to improve combustibility. According to this auxiliary air supply device, the fuel particles are reduced from the conventional 50 to 150 μm to 1
The combustibility can be greatly improved by making the particles finer to 50 to 400 μm.

As an auxiliary air supply device for the engine, there is one disclosed in JP-A-2-64258. In the auxiliary air supply device disclosed in this publication, an outlet of an auxiliary air passage having an inlet opened to communicate with a pressure source is provided so as to communicate with an injector, and the valve is opened in the middle of the auxiliary air passage at the time of injection of the injector. An air valve for supplying auxiliary air to the fuel supplied by injection is provided.

The auxiliary air supply device is, for example, as shown in FIG.
There is an internal mixing method shown in FIG. 6 and an external mixing method shown in FIG.

The auxiliary air supply device 46 of the internal mixing type is
As shown in FIG. 5, the intake passage 20 of each intake manifold 14
The injection nozzle 38 of the injector 24 is attached by a mounting body 42 to the mounting hole 40 facing the injection nozzle 3
8 in the partition wall 48 of the mounting body 42 facing each other at a distance.
0 is provided and the injection hole 5 continuous with this communication hole 50
2, the partition wall 48 of the injection nozzle 38 and the mounting body 42 is provided.
A mixing passage 54 is formed between the mixing passage 54 and
4, an outlet 58 of the auxiliary air passage 56 is provided so as to communicate with and open.

An auxiliary air supply device 4 of the external mixing type
6, the injection nozzle 38 of the injector 24 is mounted by a mounting body 42 in a mounting hole 40 facing the intake passage 20 of each intake manifold 14, and the mounting nozzle 40 is located near the injection nozzle 38. The partition wall 48 of the body 42 is provided with a communication hole 50, an injection hole 52 continuous with the communication hole 50, and the mixing passage 5 communicating with the injection hole 52.
4 is formed in the mounting body 42, and the outlet 58 of the auxiliary air passage 56 is provided in the mixing passage 54 so as to communicate therewith.

[0007]

By the way, in the conventional auxiliary air supply device for an engine, the amount of auxiliary air mixed in the fuel injected and supplied by the injector can achieve the intended purpose even if it is excessively large. First, it is necessary to properly adjust the amount of auxiliary air supplied. Further, since the amount of auxiliary air mixed in with the fuel becomes a part of the amount of intake air to the engine, it is necessary to reduce the main amount of intake air adjusted by the throttle valve.

In particular, in an operating state in which the intake air amount to the engine is small, such as when the engine is idling, when the amount of auxiliary air mixed in with the fuel is large, the throttle valve is closed even if it is closed. As a result, the engine speed does not decrease to the idle speed, which makes it difficult to control the engine.

Therefore, it is necessary to appropriately adjust the amount of auxiliary air mixed in the fuel injected and supplied from the injector according to the operating state of the engine.

However, in order to adjust the amount of auxiliary air mixed in the fuel, for example, as in the auxiliary air supply device disclosed in the above publication, an air valve consisting of a solenoid valve is provided, and the pressure for controlling this air valve is set. If a controller including a microcomputer for inputting a signal from a sensor, an air flow meter, or a crank angle sensor is provided, there is an inconvenience that the cost increases.

[0011]

In order to eliminate the above-mentioned inconvenience, the present invention provides an auxiliary air supply device for an engine, in which auxiliary air is mixed with fuel injected and injected by an injector to atomize the fuel. An auxiliary air passage communicating with an outlet is provided in an injector provided in an intake passage on the downstream side of the throttle valve, and the amount of auxiliary air introduced by the auxiliary air passage is adjusted according to the operating state of the engine. It is characterized in that the inlet of the air passage is provided at a predetermined position of the intake passage so as to have a predetermined cross-sectional area so as to communicate therewith.

[0012]

According to the structure of the present invention, in the auxiliary air supply device, the inlet of the auxiliary air passage, which has the outlet communicating with the injector, is provided at the predetermined position of the intake passage so as to have a predetermined cross-sectional area. As a result, the amount of auxiliary air supplied to the injector can be adjusted according to the operating state by appropriately selecting the position and cross-sectional area of the inlet of the auxiliary air passage. Further, the auxiliary air amount can be appropriately adjusted according to the operating state of the engine without providing a solenoid valve, an electric sensor / controller, or the like.

[0013]

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 6 show an embodiment of the present invention. In FIG. 1, 2 is an engine, 4 is an air cleaner, 6 is an intake duct, 8 is a throttle body, 10 is a throttle valve, 12 is an air chamber, 14 is an intake manifold, 16 is an exhaust manifold, and 18 is an exhaust pipe.

The engine 2 includes an air cleaner 4, an intake duct 6, a throttle body 8 and an air chamber 12.
An intake passage 20 communicating with each combustion chamber (not shown) is formed by the respective intake manifolds 14 via. A throttle valve 10 is provided in the throttle body 8 in the middle of the intake passage 20. Also, in the engine 2,
An exhaust passage 22 is provided that communicates with the outside from each combustion chamber via an exhaust manifold 16 and an exhaust pipe 18.

The engine 2 includes a throttle valve 10
An injector 24 for injecting and supplying fuel to each combustion chamber is provided in the intake passage 20 on the downstream side of the intake manifold 1 for example.
It is attached to 4 and provided. Each injector 24 is connected to a fuel distribution pipe 26. A fuel pipe 28 is connected to the fuel distribution pipe 26. The fuel pipe 28 is connected to a fuel tank (not shown).

The injector 24 is, for example, as shown in FIG.
As shown in FIG. 6, the solenoid 32 and the spring 3 are provided in the main body 30.
4 is provided with a plunger 36 that is reciprocally moved, and an injection nozzle 38 that is opened and closed by the plunger 36 and injects fuel is provided on the tip end side of the main body 30. The injector 24 is provided, for example, by being attached by a mounting body 42 to a mounting hole 40 facing the intake passage 20 of each intake manifold 14. Reference numeral 44 is a seal member.

The engine 2 is provided with an auxiliary air supply device 46 for atomizing the fuel by injecting the auxiliary air into the fuel injected and supplied from the injector 24. The auxiliary air supply device 46 is, for example, of the internal mixing type shown in FIG.
There is an external mixing method shown in FIG.

The auxiliary air supply device 46 of the internal mixing type is
As shown in FIG. 5, the intake passage 20 of each intake manifold 14
The injection nozzle 38 of the injector 24 is attached by a mounting body 42 to the mounting hole 40 facing the injection nozzle 3
8 in the partition wall 48 of the mounting body 42 facing each other at a distance.
0 is provided and the injection hole 5 continuous with this communication hole 50
2, the partition wall 48 of the injection nozzle 38 and the mounting body 42 is provided.
A mixing passage 54 is formed in a gap shape between and, and an outlet 58 of an auxiliary air passage 56 is provided in the mixing passage 54 so as to communicate therewith.

The auxiliary air supply device 4 of the external mixing type
6, the injection nozzle 38 of the injector 24 is mounted by a mounting body 42 in a mounting hole 40 facing the intake passage 20 of each intake manifold 14, and the mounting nozzle 40 is located near the injection nozzle 38. The partition wall 48 of the body 42 is provided with a communication hole 50, an injection hole 52 continuous with the communication hole 50, and the mixing passage 5 communicating with the injection hole 52.
4 is formed in the mounting body 42, and the outlet 58 of the auxiliary air passage 56 is provided in the mixing passage 54 so as to communicate therewith.

As described above, in the auxiliary air supply device 46 of the engine 2 in which the auxiliary air is mixed with the fuel injected and supplied from the injector 24 to atomize the fuel, as shown in FIG. An auxiliary air passage 56 that communicates with an outlet 58 of the injector 24 provided in the side intake passage 20 is provided.

In this auxiliary air passage 56, in order to adjust the amount of introduced auxiliary air in accordance with the operating state of the engine 2, the inlet 60 is located at a predetermined position in the intake passage 20 and has a predetermined cross-sectional area A.
Is provided as a communication opening. The auxiliary air passage 56 is
It is formed by the auxiliary air pipe 62. Auxiliary air pipe 62
Is provided in communication with the throttle body 8 and each injector 24.

More specifically, the inlet 60 of the auxiliary air passage 56.
As shown in FIG. 2, the positions of the positions are located at predetermined positions close to the valve end edge 10e of the throttle valve 10 in the closed state so as to straddle the intake passages 20 on the upstream side and the downstream side of the valve end edge 10e, respectively. The first inlet portion 60U and the second inlet portion 60D are branched and provided so as to communicate with each other. Also,
The cross-sectional area of the entrance 60 branched into the first entrance 60U and the second entrance 60D is set to a predetermined cross-section A.

As described above, the auxiliary air supply device 46, which is provided at the predetermined position of the intake passage 20 with the predetermined cross-sectional area A to open the inlet 60 of the auxiliary air passage 56, has the pressure P1 (on the upstream side of the throttle valve 10). The pressure P3 of the auxiliary air passage 56 is determined by (atmospheric pressure), the pressure P2 on the downstream side of the throttle valve 10 (pressure in the air chamber or the intake manifold), and the opening state of the throttle valve 10.

As shown in FIG. 3, the throttle valve 1
The pressure P1 on the upstream side of 0 becomes slightly negative pressure when the intake air amount of the engine increases (high load / high speed operation state), but is substantially atmospheric pressure. Pressure P2 on the downstream side of the throttle valve 10
Becomes a strong negative pressure during idling operation and deceleration operation, and gradually approaches atmospheric pressure as the engine intake air amount increases. The pressure P3 of the auxiliary air passage 56 is changed depending on the position of the intake passage 20 which is communicated with the inlet 60 and the cross-sectional area of the inlet 60, but is always changed between the pressure P1 and the pressure P2. The pressure P3 is changed by selecting the position and the cross-sectional area of the inlet 60 communicating with the intake passage 20 and can be set to a desired characteristic.

The amount of auxiliary air supplied to the injector 24 by the auxiliary air passage 56 is basically C.A.
(ΔP) ^1/2 . Here, C is a flow coefficient, A is a cross-sectional area, and ΔP is a pressure difference. C and A are substantially constant.
From this, the amount of auxiliary air is determined by the pressure difference ΔP. This pressure difference ΔP becomes a pressure difference (| P3-P2 |) before and after the auxiliary air passage 56 of the injector 24, as is clear from the figure.

In this way, by introducing the auxiliary air passage 56 by setting the characteristic of the pressure P3 by appropriately selecting the position and cross-sectional area of the inlet 60 of the auxiliary air passage 56 communicating with the intake passage 20. The amount of auxiliary air to be supplied can be adjusted according to the operating state of the engine 2, for example, as shown in FIG.

Next, the operation will be described.

When the engine 2 is in operation, the air cleaner 4
A mixture of the air taken in from the engine and the fuel injected and supplied from the injector 24 is supplied to the combustion chamber. At this time, the auxiliary air is mixed into the fuel injected and supplied from the injector 24 by the auxiliary air supply device 46, and the combustibility is improved by atomizing the fuel.

The amount of auxiliary air supplied to the injector 24 by the auxiliary air supply device 46 depends on the throttle valve 10
Of the pressure P3 of the auxiliary air passage 54 set with respect to the pressures P1 and P2 on the upstream side and the downstream side of the engine 2
It can be adjusted according to the driving state of.

The characteristic of the pressure P3 is determined by the position of the inlet 60 communicating with the intake passage 20 and the selection of the cross-sectional area, and the amount of auxiliary air supplied to the injector 24 by the auxiliary air passage 56 is used to operate the engine 2. Depending on the condition
For example, it can be adjusted as shown in FIG.

That is, as shown in FIG. 4, during the idling operation, the auxiliary air amount in the auxiliary air passage 56 can be substantially eliminated by setting P3 to a value substantially equal to P2. As a result, when the amount of auxiliary air mixed into the fuel is large in an operating state in which the intake air amount into the engine 2 is small, such as when the engine 2 is idling, the throttle valve is closed, The inconvenience that the engine speed does not decrease to the idle speed and the control of the engine becomes difficult can be eliminated by substantially eliminating the auxiliary air amount.

Further, as shown in FIG. 4, as the throttle valve 10 is opened and the engine 2 is gradually brought into a high speed operation state, the amount of auxiliary air in the auxiliary air passage 56 can be increased. Accordingly, in the acceleration operation state or the traveling operation state, the auxiliary air can be mixed with the fuel injected and supplied from the injector 24 to atomize the fuel,
The combustibility can be improved, and the fuel consumption rate and the exhaust gas harmful component value can be improved.

At this time, P3 is set so that a sufficient pressure difference (| P3-P2 |) can be secured in order to supply a sufficient amount of auxiliary air. However, the maximum value of the auxiliary air amount is determined by the passage diameter and the like, and therefore, as shown in FIG. This characteristic tends to be preferable for the fuel injected and supplied from the injector 24.

As described above, the amount of auxiliary air mixed with the fuel injected and supplied from the injector 24 can be appropriately adjusted according to the operating state of the engine 2.

As described above, the auxiliary air supply device 46 is provided with the inlet 60 of the auxiliary air passage 56 which opens the outlet 58 to the injector 24 so as to be opened at the predetermined position of the intake passage 20 as the predetermined cross-sectional area A. There is. As a result, the amount of auxiliary air supplied to the injector 24 is equal to that of the auxiliary air passage 5
By arbitrarily selecting the position and cross-sectional area of the inlet 60 of No. 6, it is possible to set any characteristic, and it is possible to adjust according to the operating state of the engine 2 without impairing the operating state during idling operation. Become. Further, the auxiliary air amount can be appropriately adjusted according to the operating state of the engine 2 without providing a solenoid valve, an electric sensor / controller, or the like.

Therefore, by appropriately selecting the position and cross-sectional area of the inlet 60 of the auxiliary air passage 56, the injector 2
The amount of auxiliary air mixed in the fuel to be injected and supplied in No. 4 can be set to an arbitrary characteristic, and can be appropriately adjusted according to the operating state of the engine 2 without impairing the operating state during idling operation. Moreover, since the auxiliary air amount can be adjusted by appropriately selecting the position and cross-sectional area of the inlet 60 of the auxiliary air passage 56 without providing a solenoid valve, an electric sensor / controller, or the like, the configuration is simple and the cost is low. There is no rise.

[0038]

As described above in detail, according to the present invention, the amount of auxiliary air mixed in the fuel injected and supplied from the injector is controlled by operating the engine by appropriately selecting the position and the cross-sectional area of the inlet of the auxiliary air passage. It can be adjusted appropriately according to the condition, and the amount of auxiliary air can be adjusted by appropriately selecting the position and cross-sectional area of the inlet of the auxiliary air passage without providing a solenoid valve or electrical sensor controller. Is simple and does not increase costs.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an auxiliary air supply device for an engine showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a valve body portion of a throttle valve.

FIG. 3 is an explanatory diagram showing a relationship between vehicle speed and pressure.

FIG. 4 is an explanatory diagram showing the relationship between vehicle speed, throttle valve opening, and air amount.

FIG. 5 is a sectional view of an injector.

FIG. 6 is a sectional view of another injector.

[Explanation of symbols]

 2 Engine 4 Air Cleaner 6 Intake Pipe 8 Throttle Body 10 Throttle Valve 12 Air Chamber 14 Intake Manifold 16 Exhaust Manifold 18 Exhaust Pipe 20 Intake Passage 22 Exhaust Passage 24 Injector 26 Fuel Distribution Pipe 28 Fuel Pipe 40 Mounting Hole 42 Mounting Body 44 Sealing Member 46 Auxiliary Air Supply Device 54 Mixing Passage 56 Auxiliary Air Passage 58 Outlet 60 Inlet

Claims (1)

[Claims] 1. An auxiliary air supply device for an engine, which mixes auxiliary air into fuel injected and injected by an injector to atomize the fuel. In an injector provided in an intake passage downstream of a throttle valve of the engine, an outlet is opened for communication. An auxiliary air passage for controlling the amount of auxiliary air introduced by the auxiliary air passage according to the operating state of the engine, and an opening for communicating the inlet of the auxiliary air passage with a predetermined cross-sectional area at a predetermined position of the intake passage. An auxiliary air supply device for an engine, which is provided by